Preparation of arylthioglycollic acids



' radiating 18,1925.

Asa wILLARnJoYcE. or NEWARK, new JERSEY, 'AssIoNon 'ro rnsz cnnmrcar. Form- 'D. A.T101\T, INCORPORATED, on NEW YORK, N. YWA conrozaarron or DELAWARE.

PREPARATION or ARYLTHIOGLYCO'LLIC acrns."

K Drawing.

To all whom it may concern.

Be it known that I, AsA WILLARD J oYoE, a citizen of the United States, residing at Newark, in the county of Essex and State of 5 New Jersey, have invented certain new and j useful Improvements in the Preparation of Arylthioglycollic Acids, of which the following is a full, clear, and exact description,

such as will enable others skilled in the art particularly to a process for the production of arylthioglycollic acids. I V

An object of the invention is to provide a process which is simple and efiicientin operation. f A further object'of the invention is to provide a .process which utilizes substances of low initial cost, thereby rendering such process economical.

Another object of the invention is to pro vide a processwhich will produce arylthic 2 glycollic acids in a substantially purestate and which will give good yields. c Other objects of the invention will in part c be-obvious and will. in partappear hereinafter. so

severalsteps and the relation and order of one orm'ore of such stepswith respect to each of the others thereof, which will beexemplified in the process hereinafter disclosed, and the scope of the application of which will be indicated in the claims.

In the practice of the invention,'there may be prepared intermediates which are utilizable in the manufacture of thio indi-- 4o 'goid vat dyes, more particularlyarylthioglyv"collie acids The process comprises the elimfrom an ortho tion of the corresponding arylthioglycollic acid. This may be accomplished by subjectinga' solution of a diazo derivative of an ortho amino .arylthioglycollic "acid to treat- I ment'with an aliphatic alcohol, as mythyl,

ethyl, propyl, 'etc;, and a reducing agent,

Application filed July 5, 1924. Serial No. 724,527.

reducing agent, it is preferred tpyh'ave the The invention accordingly comprises the "to remove the iron, it is advantageous to .add tothe alkaline mixture a small quantity of such as a-metai'of the iron group, fo r example iron and zinc or stannous chloride, sodium 'stannite and sodium hydrosulfite. The proportions in which the various constituents may be used are those which correspond to the stoichiometrical requirements, 5 and the temperature at which the reaction is carried out is preferably room temperature, that is, about 20 C. When using a metal of the iron group or stannous chloride as the reaction take place in the. presence of an acid, as sulphuric and phosph0ricwhereas, when sodium stannite or sodium hydrosulfits are employed the reaction should take place in an alkaline medium. The yield of the arylthioglycollic acidis good, and the productis substantially pure,-it being relativel'y free from oxy and alkoxy compounds.

As illustrative embod mentsof a manner in which the invention 1 ay be carried'into practice, the followin' examples are pre: I sented. The parts are y weight.

Example 1.,

, Take 254 parts of the sodium salt of 5 chloro 3 methyl 2 amino phenyl thioglycollic acid, dissolve in "1,500 parts of water, and mix 7 with a solution'containin 75 parts of sodium nitrite in 200 parts 0 water. The solu-. Y

tion thus obtained is added, gradually and with constant stirring, to a mixture of 200 parts of sulphuric acid and 1,000 parts ofice, at such a rate that the temperature will be maintained at orbelow 10 C. The diazotization having been completed, the reaction mixture is filtered and slowly added'to an equal volume of alcohol containing 250 partsof concentrated sulphuric acid and from about 75 to parts of iron, which may be in the fo'rmof filings, borings, etc. When the presence of the diazo compound can no longer bs-detected, a sodium hydroxide solution (40 E6.) is added until' the mixture is Slightly alkaline; In order sodium sulfideand to raise the temperature to i "about 60; to-65 C, The iron ,is precipitated "as the sulfide and may be removed by filtermg The alcohol: may bere'r'novedfrom the time by distillation and reclaimed, if it is'so desired. The clear liquor obtained is allowed to cool and is then poured into an excess of an acid, such as sulphuric, whereupon the compound 5 chloro 3 methyl phenyl thioglycollic acid precipitates out in the form of small white crystals.

-Emample H.

The process for diazot-ization as described in Example I is carried out and the product thereof is gradually added to an equal vol ume of alcohol containing 200 parts of stannous chloride or containing 250 parts of concentrated sulphuric acid and from 140 to 150 parts of granulated zinc. The procedure following the reducing action is as that described in Example I and there results in good yield 5 chloro 3 methyl phenyl thioglycollie acid.

Example [11.

I A diazo solution obtained as described in Example I is made slightly alkaline, for example with sodium carbonate, whereupon it is added to an equal volume of alcohol containing sodium stannite or sodium hydrosulfite. The diazo group is removed and the thioglycollic acid corresponding is obtained. i

The process described in the foregoing examples is applicable for the preparation of thioglycollic acids with various aryl groupings, which aryl groupings may be variously substituted. This substitution the invention comprises a process for the preparation of a thioglycollic acid contain- 1ng an aryl grouping, which grouping may be variously-substituted.

Since certain changes may be made in carrying out the above process without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the followmg claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I i I claim as new and desire to secure by Letters Patent, is:

1. A process for the preparation of arylthioglycollic acids which comprises treating an ortho diazo arylthioglycollic acid with an aliphatic alcohol and a reducing agent.

2. A process for the preparation of arylthioglycollic acids which comprises treating an ortho diazo arylthioglycollic acid with an aliphatic alcohol and a reducing agent in the presence of an acid.

3. A process for the preparation of arylthioglycollic acids which com rises treating an ortho diazo arylthioglycolhc acid with an aliphatic alcohol and a reducing agent in the presence of sulphuric acid.

A. A process for the preparation of arylthioglycollic acids which comprises treating an artho diazo arylthioglycollic acid with an aliphatic alcohol and a metal of the iron group.

5. A prmess for the preparation of arylthioglycollic acids which comprises treating an ortho diazo arylthioglycollic acid with an aliphatic alcohol and iron.

6. A process for the preparation of arylthioglycollic acids which comprises treating an ortho diazo arylthioglycollic acid with an aliphatic alcohol and iron in the presence of an acid. 7. A process for the preparation of arylthioglycollic acids which comprises treating an ortho diazo arylthioglycollic acid with an aliphatic alcohol, iron and sulphuric acid.

8. A process for the preparation of arylthioglycollic acids which comprises treating an ortho diazo arylthioglycollic acid with ethyl alcohol, iron and sulphuric acid.

9. A process for the preparation of 5 chloro 3 methyl phenyl thioglycollic acid which comprises treating a solution containing 5chloro 3 methyl 2 diazo phenyl thioglycollic acid with an aliphatic alcohol and a reducing agent.

10. A process for the preparation of 5 choro 3 methyl phenyl thioglycollic acid which comprises treating a solution containing 5 chloro 3 methyl 2 diaz'o phenyl thioglycollic acid with an aliphatic alcohol and non.

11. A process for the preparation of 5 chloro 3 methyl phenyl thioglycollic acid which comprises treating a solution containing 5 chloro 3 methyl 2 diazo phenyl thioglycollic acid with an aliphatic alcohol and iron in the presence of acid.

12. A process for the preparation of 5 chloro 3 mcthylphenyl thioglycollicf'acid which comprises treating a solution containing 5 chloro 3 methyl 2 diazo phenyl thioglycollic acid with ethyl alcohol, iron and sulphuric acid,

In testimony whereof I affix my signature;

I ASA wILLAnnJoYoE; 

